A rare case of renal cell carcinoma associated with renal artery aneurysm in solitary kidney is reported. The patient is a 63-year-old woman with asymptomatic macrohematuria as CC, who previously received left nephrectomy (for which underlying disease is unknown). Excretory pyelography, abdominal CT and right renoarteriography revealed a 6 X 6 cm-tumor at the center of the right kidney, comprising the middle calices and a 16 X 18 mm-saccular aneurysm at the first bifurcation of the renal artery. No remote metastasis was revealed. Aneurysmectomy and partial nephrectomy (three-quarter of right middle and lower calices) were simultaneously performed in situ. The renal cell carcinoma was pT2b, of clear cell subtype and grade 1, and no calcification of the aneurysmal wall was observed. Anuria lasted for 21 postoperative days, but thereafter diuresis appeared. Renal function after 3 post-operative months remains kept as follows: BUN, 26 +/- 7 mg/dl; serum creatinine, 26 +/- 0.6 mg/dl; creatinine clearance, 20.1 ml/min. Now, after 18 postoperative months, the patient is already returning to work, with neither relapse nor need of dialysis.